Ann Francis Shipwreck Lock Code ANCE: CT Scan Opens a Padlock Sealed Since 1583

The Ann Francis shipwreck lock code ANCE is four letters long, and it stayed secret for 443 years. On 4 November 2026, Cardiff University and Amgueddfa Cymru – Museum Wales announced that researchers had read the combination inside a small brass padlock from the wreck and opened it the way its owner once did — by turning the rings, not by forcing them (Cardiff University). Information verified through 8 November 2026.

The ship behind the lock needs no embellishment. The Ann Francis, an English merchant vessel returning from Spain, was caught in a ferocious storm on the evening of 28 December 1583 and wrecked on Margam Beach, near Port Talbot (Cardiff University). Its cargo stayed under the sand for centuries.

Ann Francis shipwreck lock code ANCE, read without forcing the lock

Nobody picked this lock. Nobody cut it.

Dr David Williams, a research associate at Cardiff University’s School of Engineering, examined the mechanism with micro-CT scanning, equipment his facility normally uses to study bones and other biological structures (Cardiff University). “Micro-CT scanning allowed us to look inside the lock without damaging it,” Williams said (Cardiff University).

The detail mattered. Inside, each rotating ring carries a notch. Line the notches up and the locking bar can slide free. Williams built a detailed 3D image of the interior, matched the notches to the letters above them, and read off the combination (Cardiff University). Back at the museum, curators aligned the rings to A, N, C, E — and the grit-covered key came loose (Gizmodo).

It took a few attempts to get scans clear enough. The first images were promising, a later attempt went badly, and only a third approach produced pictures detailed enough to trust (ZME Science). That patience had a conservation payoff too: opening the lock let specialists remove grit trapped inside, grit that would have kept damaging the mechanism if it had stayed sealed (Gizmodo).

A 400-year-old shipwreck padlock CT scan beats 1,296 guesses

The lock is tiny. Its four rings each carry six letters, which gives 1,296 possible combinations (ZME Science). Peter Hughes, the metal detectorist who found it, tried for years. “I tried to unlock it for about 20 years, I tried moving the dials, finding the right combinations, and I failed,” he told the BBC, in remarks reported by ZME Science (ZME Science).

Brute force was never a good option anyway. Repeated turning risked wearing a mechanism that had survived the sea, sand and four centuries of burial, and museum staff needed the object intact, not just open (ZME Science). The 400-year-old shipwreck padlock CT scan solved that tension: look first, turn once.

Locks like this, sometimes called Nuremberg locks, circulated in Elizabethan Britain, and a comparable example in the British Museum opens with the letters MARCI (ZME Science). What sets the Ann Francis lock apart, curator Alastair Willis noted, is condition plus context: Elizabethan combination locks are known in Britain, but this one is in exceptionally good condition and tied to a dated wreck (Cardiff University).

What the Margam Beach Ann Francis treasure hoard actually held

Hughes recovered most of the hoard over 21 years, between 1996 and 2017, after dredging and storms stripped sand from Margam Beach (Cardiff University). His finds ran to roughly 870 gold and silver coins, alongside navigational equipment, cooking utensils and personal belongings (ZME Science). Some coins came from Germany and Portugal; others were minted in Mexico, early examples of Spanish colonial coinage (ZME Science).

The ship’s ownership explains the mixed money. Museum Wales research identifies the owner as Francis Shaxton, a King’s Lynn merchant; Shaxton and his father, also named Francis, were described as notorious smugglers running a fleet of trading ships (ZME Science). The Ann Francis had sailed to Spain in October 1583 carrying wheat, and its return cargo included payment in gold and silver, some of it originating in Spain’s American colonies (ZME Science). After the wreck, locals looted the vessel, and court records describe a dispute over the salvaged cargo, with an inventory listing cannon, anchors, spices, money and three chests with broken locks (ZME Science).

Was this padlock on one of those chests? Possibly. Nobody can establish that link with certainty (ZME Science). The museum’s own account stays careful: found near Spanish silver coins and two coin weights, the lock is believed to have secured a small chest holding items of significant value — valuables that survived, or documents and textiles that did not (Cardiff University).

And ANCE itself? No explanation has been found. It may have held a personal meaning for its owner; it may simply have been a convenient setting (ZME Science). Willis put the open end plainly: now the code is solved, “we are left wondering if the code meant something to its owner” (Cardiff University).

Hughes, seeing it open at last, was blunter about his own two decades of failure: he tried hundreds of times, unsuccessfully, “and thankfully, technology and science has taken over” (Gizmodo).

The lock is now on display with the rest of the hoard, including rare gold coins from the reign of Ferdinand and Isabella of Spain and a boatswain’s whistle from the wreck (Cardiff University). The Tides of Treasure exhibition Swansea visitors can see at the National Waterfront Museum runs until September 2027, and the acquisition — supported by the Welsh Government — forms part of that museum’s reimagining as a museum of the sea (Cardiff University).

Analysis: the headline trick here is a scanner reading a password. The quieter achievement is restraint. A fragile object kept its evidence because the team refused the quick win of 1,296 forced attempts, and the answer they got — four plain letters, meaning unknown — is more honest history than any invented treasure story would be.

Photo: Gareth James, via Wikimedia Commons (CC BY-SA 2.0)

Sources

1. https://www.cardiff.ac.uk/news/view/3118948-ct-scans-help-unlock-400-year-old-mystery
2. https://www.zmescience.com/science/news-science/scientists-used-ct-and-finally-opened-a-400-year-old-lock-from-a-welsh-shipwreck/
3. https://gizmodo.com/a-smugglers-padlock-stayed-locked-for-400-years-and-scientists-just-cracked-its-code-2000835694
4. https://arkeonews.net/ct-scans-crack-the-code-of-a-400-year-old-shipwreck-lock/